The Camaquã Extensional Basin: Neoproterozoic to Early Cambrian Sequences in Southernmost Brazil (original) (raw)

2000, Revista Brasileira de Geociências

The C.rmaquã lasin is an extensional post-orogenic and pre-cratonic rift system of Neoproterozoic-Early Cambrian age locatecl in the Gaúcho Shield, Rio Grande do Sul, southernmost Brazil. The basin is divided into a series of small sub:basins which were filleã with the Camaquã Group, a thick (>9,000 m) unit composed of three formations: (i) the siliciclastic Maricá Formation, (ii) the volcano-sedimentary Crespos.Formation and (iii) the siliciclastic Santa BárbaraFormation. These units correspond to three majorstratigraphic sequences, and are divided into h,igher order sequences. Provenance and paleocurent analysis of the siliciclaitic deposits show a closelelationshþ of the sourcearea with the lithologies that occur today in the neighborhood of these deposits, suggesting that ño important lateral transport tõok place along the border faults. Paleocuffent measurements indicate a northern position for the marine body that cyclically invaded the basin.